A contactless wireless power transmission system is an energy transfer method of electromagnetically transferring energy by removing a line in the existing method of transmitting energy through a wired line and using the energy as power for an electronic device. The contactless wireless power transmission system includes an electromagnetic induction method and a resonant method. The electromagnetic induction method is a method of generating, by a power transmission unit, a magnetic field through a power transmission coil (primary coil), locating a reception coil (secondary coil) at the place where current can be induced, and transferring power to the reception coil. In the resonant method, energy is transmitted using a resonant phenomenon between a transmission coil and a reception coil. A system in which the resonant frequency of the primary coil and the resonant frequency of the secondary coil are the same is configured to use resonant mode energy coupling between the coils.
The existing wireless power transmission system of the induction method is a product applied to a low energy portable device (smartphone) of maximum 5 W (based on the reception unit) and charging a portable device when it is placed on a wireless charger (transmission unit) without plugging a separate power line into the portable device, and has already been widely introduced in the market.
Recently, a technology for wirelessly transmitting higher power using a magnetic induction method, that is, the same principle, is introduced. An international standardization task for applying the technology to products is in progress.
Representative products to which high-output wireless power transmission using the magnetic induction method may be applied are home appliances for kitchen. Common home appliances for kitchen require transmission support of 200 W˜2.4 kW power.
Accordingly, the present invention proposes a resonant structure, that is, a core element of a wireless power transmission system so that an appliance wirelessly operates when it is placed at a specific location of a table (if a transmission unit is located under the table) even without connecting a separate power line by applying a wireless power transmission system to such home appliances for kitchen.